The present invention relates to the air or gas sealing arrangements for rotary drums such as high temperature rotary kilns, or more specifically, a flexible seal for sealing the opening between a rotating drum and a stationary hood to prevent the flow of gaseous fluids into and out from the ends of the rotary drum.
It is a common practice to employ a flexible seal at the ends of a rotary kiln to seal the annular space between the rotating drum of the kiln and the stationary housing at each end of the kiln. It is desirable to seal these open spaces due to the high temperatures, often exceeding 2500F. in cement applications, found within the kilns. Sealing these spaces provides substantial benefits by confining toxic gases within the kiln and increasing energy efficiency through prevention of loss of the heated gas.
Overlapping leaf type seals such as U.S. Pat. Nos. 4,405,137 and 5,571,269 incorporate metal leaves that flex with the eccentric motion of the rotating drum. Such movement opens up small gaps in between the leaves themselves and in between the leaves and rotating drum. Such openness causes a drop in efficiency of the sealing arrangement.
The present invention incorporates a framework of pivoting arms and a metallic or non-metallic riding surface that supports a fabric seal such that there is 360 degree contact between the seal and rotating drum surface. The fabric is continuous about the rotating drum and has only 1 overlap that does not open up. The metallic or non-metallic riding segments are overlapping; however no gaps open up since they lay flat and slide on the rotating drum parallel to the direction of rotation.
The present invention pertains to a rotary seal assembly for a rotary kiln having a hood and a rotary drum with an opening formed between the drum and the hood, and an end. The rotary seal assembly comprises a flexible framework arrangement that attaches to the end. The rotary seal assembly comprises a riding surface that engages the drum as the drum rotates and connects with the framework arrangement in response to the movement of the drum as the drum rotates end. The rotary seal assembly comprises a seal that is supported by the riding surface and is in essentially 360 degree contact with the drum when it is rotating and seals the opening between the drum when it is rotating in the hood to prevent fluid flow into and out of the end.
The present invention pertains to a method for sealing an opening formed between a drum and a hood. The method comprises the steps of attaching a flexible framework arrangement to the hood. There is the step of connecting a riding surface with the framework arrangement so the riding surface engages the drum as the drum rotates in response to the movement of the drum as the drum rotates. There is the step of sealing the opening between the drum when it is rotating in the hood to prevent fluid flow into and out of the end with a seal that is supported by the riding surface and is in essentially 360 degree contact with the drum when it is rotating.
An improved rotary seal assembly for kiln drums and the like utilizes a series of overlapping metal segments mounted to a hood surrounding the drum. The metal segments are connected to the hood via pivoting arms such that there are movable joints at the hood mounting surface and the sealing segments. Pivot arms are affixed to the hood via a mounting ring and intermediate clamping ring. Fabric covers the permeable metal skeleton and is affixed to the hood end via the fixed intermediate and end clamping rings and affixed to the sealing end via a tension device comprised of fabric tape, metal buckles, and metal tension springs. A braided rope packing seals off the open gap between the intermediate clamping ring and the mounting ring.